Elsevier

Materials Letters

Volume 264, 1 April 2020, 127316
Materials Letters

Synthesis of spindle-like CuO nanoparticles by using cathode glow discharge electrolysis plasma

https://doi.org/10.1016/j.matlet.2020.127316Get rights and content

Highlights

  • Spindle-like CuO nanoparticles (NPs) was prepared by CGDEP technique.

  • Pt needle point and Cu foil were acted as cathode and anode, respectively.

  • The optimized electrolyte was 2.5 g L−1 NaNO3 containing 1.0 g L−1 CTAB.

  • The particle diameters of spindle-like CuO NPs are about 250–350 nm long.

Abstract

Spindle-like CuO nanoparticles (NPs) were prepared in a single-step approach by using a cathode glow discharge electrolysis plasma (CGDEP) technique with 2.5 g L−1 NaNO3 as an electrolyte and 1.0 g L−1 cetyltrimethylammonium bromide (CTAB) as a stabilizer. When a sufficiently high voltage (>280 V) was applied, plasma was generated around the Pt needle point cathode. The copper foil anode was gradually consumed and black CuO NPs appeared. The active species formed during the CGDEP process were recorded on an optical fiber spectrometry. The structure and morphology of the CuO NPs were characterized by XRD and SEM. The results showed that spindle-like CuO NPs with the length of 250–350 nm were formed at 300 V discharge voltage.

Introduction

CuO is an important semiconductor that has been widely used in catalysis, optoelectronics, information storage, and nanosensor [1]. When prepared in nanoparticle (NP) form, it is known that both the size and morphology of the NPs can significantly influence the physical and chemical properties of the materials. Therefore, previous studies have focused on the preparation of CuO NPs with variety of morphologies, including spheres, wires, rods and flowers [2], [3], [4], [5], [6], [7]. Many methods have been reported for the synthesis of CuO NPs, such as sol-gel method [3], sonochemical synthesis [4], hydrothermal method [5], alcohothermal process [6] and thermal decomposition [7]. As described herein, it is also possible to prepare CuO NPs using electrolysis plasma technique.

The glow discharge electrolysis plasma (GDEP) is one of the simplest methods to obtain a stable solution plasma, in which two electrodes, for example, a carbon rod and needle-like Pt, are introduced into the solution [8]. When a sufficiently high voltage is employed in the conventional electrolysis, plasma is directly produced in the solution around the needle-like Pt electrode. At the same time, various active species such as H·, O·, HO· are produced and some unusual chemical reactions are initiated [9]. Over the past two decades, GDEP has been widely employed for water purification [10], surface modification [11], synthetic chemistry [12], and spectral analysis [13]. However, there are few reports for the preparation of NPs from bulk material using GDEP [8].

Herein, the application of GDEP as a simple and environmentally-friendly method for the preparation of CuO NPs has been investigated. It is found that spindle-like CuO NPs can be produced by cathode glow discharge electrolysis plasma (CGDEP). The active species in the CGDEP were determined by optical fiber spectrometer for clarifying the formation processes of CuO. The structure, morphology and size of spindle-like CuO NPs were characterized by XRD and SEM.

Section snippets

Materials

NaNO3 and cetyltrimethylammonium bromide (CTAB) were analytical purity and supplied by Sinopharm Reagent Co., Ltd. Copper foil (>99.99%) was supplied by Shanghai Chemical Reagent Corporation.

Synthesis of CuO nanoparticles

The experimental setup contains a high voltage power supply (LW100J1 DC power supply, China) and a reactor as shown in Fig. 1. The reactor is a 200 mL quartz vessel equipped with a Pt needle point cathode and copper foil anode. The gap between the cathode and anode is 10 mm. The reactor vessel was charged

Spectral characteristics of CGDEP

Fig. 2 shows a typical emission spectrum of CGDEP in the range of 200–900 nm. As can be seen from Fig. 2, the lines at 283.0, 289.0 and 309.0 nm are assigned to OH bands (A2Σ+ → X2Π) [14]. Since a significant amount of water is vaporized during discharge, electrons collide with the water molecules to generate OH+, which impacts with electrons to produce a large number of OH radicals [13]. Ionic lines attributed to OII (397.3 and 463.1 nm) and atomic lines attributed to H (Hβ at 486.1 nm and Hα

Conclusions

The CGDEP is demonstrated to be a very promising method for the direct transformation of a Cu foil precursor to CuO NPs. Advantages of this simple one-step method include low operational costs and a lack of toxic by-products. XRD and SEM analysis demonstrated that spindle-like CuO NPs with length of 250–350 nm prepared by this method have high purity. These novel CuO NPs are promissing candidate materials for superconductor, catalysis, photoelectrochemistry, solar-energy transformation, and

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgements

This work was supported in part by National Natural Science Foundation of China (Nos. 21961032 and 21864022), and Natural Science Foundation of Gansu Province (Nos. 17JR5RA075 and 17JR5RA077), China.

References (22)

  • B.X. Yuan et al.

    Mater. Lett.

    (2019)
  • R. Ranjbar-Karimi et al.

    Phys. B

    (2010)
  • Z.S. Hong et al.

    Mater. Lett.

    (2002)
  • R. Al-Gaashani et al.

    J. Alloys Compd.

    (2011)
  • X.Y. Wang et al.

    Electrochim. Acta

    (2012)
  • B. Jiang et al.

    Chem. Eng. J.

    (2014)
  • Q.F. Lu et al.

    Spectrochim. Acta B

    (2016)
  • J. Yu et al.

    Talanta

    (2017)
  • M. Sahooli et al.

    Mater. Lett.

    (2012)
  • H. Wang et al.

    J. Cryst. Growth

    (2002)
  • M.W. Xu et al.

    RSC Adv.

    (2012)
  • Cited by (7)

    View all citing articles on Scopus
    View full text